Butenoic acid derivatives, processes for the preparation thereof, pharmaceutical compositions comprising them, and use for the treatment of dyslipidaemia, atherosclerosis and diabetes

ABSTRACT

The present invention relates to butenoic acid derivatives of the formula I: 
     
       
         
         
             
             
         
       
     
     in which R, R 1 , R 2  and R 3  are as defined in the description,
 
and also to processes for the preparation thereof, to pharmaceutical compositions comprising them and to their use for the treatment of dyslipidaemia, atherosclerosis and diabetes.

This application is a continuation of U.S. patent application Ser. No.10/566,995, filed 2 Feb. 2006, which is a National Stage entry ofPCT/EP04/07776 filed on Jul. 14, 2004.

The present invention relates to unsaturated carboxylic acid derivativesthat can be used in the treatment of dyslipidaemia, atherosclerosis anddiabetes, to pharmaceutical compositions comprising them, and toprocesses for the preparation of these compounds.

The invention also relates to the use of these compounds for thepreparation of medicaments for the treatment of dyslipidaemia,atherosclerosis and diabetes.

In most countries, cardiovascular disease remains one of the majordiseases and the main cause of death. About one third of men develop amajor cardiovascular disease before the age of 60, with women showing alower risk (ratio of 1 to 10). With advancing years (after the age of65, women become just as vulnerable to cardiovascular diseases as men),this disease increases even more in scale. Vascular diseases, such ascoronary disease, strokes, restenosis and peripheral vascular diseaseremain the prime cause of death and handicap worldwide.

Whereas the diet and lifestyle can accelerate the development ofcardiovascular diseases, a genetic predisposition leading todyslipidaemia is a significant factor in cardiovascular accidents anddeath.

The development of atherosclerosis appears to be linked mainly todyslipidaemia, which means abnormal levels of lipoproteins in the bloodplasma. This dysfunction is particularly evident in coronary disease,diabetes and obesity.

The concept intended to explain the development of atherosclerosis wasmainly focused on the metabolism of cholesterol and on the metabolism oftriglycerides.

However, since the studies of Randle et al. (Lancet, 1963, 785-789), anovel concept has been proposed: a glucose-fatty acid cycle or Randlecycle, which describes the regulation of the equilibrium between themetabolism of lipids in terms of triglycerides and cholesterol, and theoxygenation of glucose. Following this concept, the inventors havedeveloped a novel programme, the aim of which is to find novel compoundsacting simultaneously on lipid metabolism and glucose metabolism.

Fibrates are well-known therapeutic agents with a mechanism of actionvia the “Peroxisome Proliferator Activated Receptors”. These receptorsare the main regulators of lipid metabolism in the liver (PPARαisoform). In the last 10 years, thiazolidinediones have been describedas powerful hypoglycaemiant agents in man and animals. It has beenreported that thiazolidinediones are powerful selective activators ofanother isoform of PPARs: PPARγ (Lehmann et al., J. Biol. Chem., (1995),270, 12953-12956).

The inventors have discovered a novel class of compounds that arepowerful activators of the PPARα and PPARγ isoforms. As a result of thisactivity, these compounds have a substantial hypolipidaemiant andhypoglycaemiant effect.

More specifically, the invention relates to butenoic acid-derivedcompounds of the formula I:

in which

-   -   R¹ represents a (C₆-C₁₈)aryl group, which is optionally        substituted and/or optionally fused to a saturated or        unsaturated, monocyclic or polycyclic 5- to 8-membered nucleus        optionally containing one or more hetero atoms chosen from O, N        and S, the said nucleus itself being optionally substituted; an        optionally substituted, saturated, unsaturated or aromatic 5- to        8-membered monocyclic heterocyclic group containing one or more        hetero atoms chosen from O, N and S; an optionally substituted        C₂-C₁₀ alkenyl group; a C₁-C₁₀ alkyl group;    -   R² and R³ independently represent a hydrogen atom; an optionally        substituted (C₆-C₁₈)aryl; or alternatively R² and R³ together        represent a C₃-C₆ alkylene chain; and    -   R represents a hydrogen atom; a C₁-C₁₀ alkyl group; a        (C₆-C₁₈)aryl(C₁-C₁₀)alkyl group;    -   and the salts thereof with acids or bases,        it being understood that the following compounds are excluded        from the protection:        when R³=phenyl; R=ethyl; R¹=ethyl or phenyl; and R²═H.

The acids that can be used to form the salts of the compounds of theformula I are mineral or organic acids. The resulting salts are, forexample, the hydrochlorides, hydrobromides, sulfates, hydrogen sulfates,dihydrogen phosphates, citrates, maleates, fumarates,2-naphthalenesulfonates and para-toluenesulfonates.

The bases that can be used to form the salts of the compounds of theformula I are mineral or organic bases. The resulting salts are, forexample, the salts formed with metals and especially alkali metals,alkaline-earth metals and transition metals (such as sodium, potassium,calcium, magnesium or aluminium), or with bases, for instance ammonia orsecondary or tertiary amines (such as diethylamine, triethylamine,piperidine, piperazine or morpholine) or with basic amino acids, or withosamines (such as meglumine) or with amino alcohols (such as3-aminobutanol and 2-aminoethanol).

The invention especially covers the pharmaceutically acceptable salts,but also the salts that allow a suitable separation or crystallisationof the compounds of the formula I, such as the salts obtained withchiral amines.

The invention also covers the optically active forms, stereoisomers,enantiomers, racemates and diastereoisomers of the compounds of theformula I, and also mixtures of these forms in all proportions.

The invention also includes the hydrate or solvate derivatives of thecompounds of the formula I. The term “solvate derivatives” means theproducts of addition of one or more moles of inert solvent to thecompounds of the formula I, which are formed on account of their mutualforce of attraction. The solvate derivatives are, for example, themonohydrates, dihydrates, trihydrates, etc., or alternatively thealcoholates.

The invention thus includes all the derivatives of the compounds of theformula I that are usable and acceptable in the pharmaceutical field,for instance the salts, but also the “prodrugs” of these compounds.

The term “prodrug” denotes, for example, the compounds of the formula Ithat have been modified, especially with alkyl or acyl groups, sugars oroligopeptides, these being groups that are rapidly released in the bodyto restitute the active principles according to the present invention.

The “prodrugs” also include the derivatives of the compounds of thepresent invention in the form of biodegradable polymers, such as thosedescribed, for example, in Int. J. Pharm., 115, 61-67, (1995).

The present invention also relates to mixtures of compounds of thegeneral formula I as defined above, and especially mixtures of twooptically active forms, for example two diastereoisomers, in allproportions, for example 1:1, 1:2, 1:3, 1:4, 1:5, 1:10, 1:100 or 1:1000.

Thus, the invention includes the compounds of the formula I, and alsothe pharmaceutically acceptable derivatives, salts, solvate derivativesthereof and stereoisomers thereof, including mixtures thereof in allproportions.

According to the invention, the term “aryl group” means a monocyclic orpolycyclic carbocyclic aromatic group preferably containing from 6 to 18carbon atoms. Aryl groups that may be mentioned include phenyl,naphthyl, anthryl and phenanthryl groups.

The term “alkyl” means a linear or branched hydrocarbon-based chaincontaining from 1 to 10 carbon atoms and better still from 1 to 6 carbonatoms, for example from 1 to 4 carbon atoms.

Examples of alkyl radicals are methyl, ethyl, propyl, isopropyl, butyl,isobutyl, t-butyl, pentyl, isopentyl, neopentyl, 2-methylbutyl,1-ethylpropyl, hexyl, isohexyl, neohexyl, 1-methylpentyl,3-methylpentyl, 1,1-dimethylbutyl, 1,3-dimethylbutyl, 1-ethylbutyl,1-methyl-1-ethylpropyl, heptyl, 1-methylhexyl, 1-propylbutyl,4,4-dimethylpentyl, octyl, 1-methylheptyl, 2-methylhexyl,5,5-dimethylhexyl, nonyl, decyl, 1-methylnonyl, 3,7-dimethyloctyl and7,7-dimethyloctyl.

The heterocyclic groups are monocyclic or polycyclic groups comprisinghetero atoms generally chosen from O, S and N, optionally in oxidisedform (in the case of S and N).

Preferably, at least one of the monocycles constituting the heterocyclecontains from 1 to 4 endocyclic hetero atoms and better still from 1 to3 hetero atoms.

According to the invention, the polycyclic heterocyclic nucleus consistsof one or more monocycles, each of which is 5- to 8-membered.

Examples of 5- to 8-membered monocyclic aromatic heterocyclic groups areheteroaryls, such as pyridine, furan, thiophene, pyrrole, imidazole,thiazole, isoxazole, isothiazole, furazane, pyridazine, pyrimidine,pyrazine, thiazines, oxazole, pyrazole, oxadiazole, triazole andthiadiazole.

Preferred heteroaryls that may be mentioned include pyridyl,pyrimidinyl, triazolyl, thiadiazolyl, oxazolyl, thiazolyl and thienylnuclei.

The saturated or unsaturated heterocyclic groups are heterocyclic groupsbearing no unsaturation, or comprising one or more unsaturations derivedfrom the aromatic heterocyclic groups defined above, respectively.

The term “C₂-C₁₀ alkenyl group” means an aliphatic hydrocarbon-basedgroup comprising one or more unsaturations of ethylenic type, preferably1 to 3 ethylenic unsaturations. Preferred examples of such C₂-C₁₀alkenyl groups are especially vinyl groups and CH₂═CH—CH₂═CH— groups.

When R² and R³ together represent a C₃-C₆ alkylene chain, it ispreferable for R², R³ and the carbons to which they are attached to forma cyclopentene or a cyclohexene.

The aryl and heterocyclic groups and nuclei are optionally substitutedby one or more of the following radicals:

trifluoromethyl; a halogen atom; a monocyclic, bicyclic or tricyclicaromatic heterocyclic group comprising one or more hetero atoms chosenfrom O, N and S; and optionally substituted by one or more radicals T asdefined below; a group Het-CO— in which Het represents an aromaticheterocyclic group as defined above optionally substituted by one ormore radicals T; a C₁-C₆ alkylenediyl chain; a C₁-C₆ alkylenedioxychain; nitro; cyano; (C₁-C₁₀)alkyl; (C₁-C₁₀)alkylcarbonyl;(C₁-C₁₀)alkoxycarbonyl-A- in which A represents (C₁-C₆)alkylene,(C₂-C₆)alkenylene or a bond; (C₃-C₁₀)cycloalkyl; trifluoromethoxy;di(C₁-C₁₀)alkylamino; (C₁-C₁₀)alkoxy(C₁-C₁₀)alkyl; (C₁-C₁₀)alkoxy;(C₆-C₁₈)aryl optionally substituted by one or more radicals T;(C₆-C₁₈)aryl(C₁-C₁₀)alkoxy-(CO)_(n)— in which n is 0 or 1 and aryl isoptionally substituted by one or more radicals T;(C₆-C₁₈)aryloxy(CO)_(n)— in which n is 0 or 1 and in which aryl isoptionally substituted by one or more radicals T; (C₆-C₁₈)arylthio inwhich aryl is optionally substituted by one or more radicals T;(C₆-C₁₈)aryloxy(C₁-C₁₀)alkyl(CO)_(n)— in which n is 0 or 1 and in whicharyl is optionally substituted by one or more radicals T; a saturated orunsaturated, monocyclic 5- to 8-membered heterocycle containing one ormore hetero atoms chosen from O, N optionally substituted by one or moreradicals T; (C₆-C₁₈)arylcarbonyl-B—(CO)_(n)— in which n is 0 or 1; Brepresents (C₁-C₆)alkylene or (C₂-C₆)alkenylene and aryl is optionallysubstituted by one or more radicals T; (C₆-C₁₈)aryl-C—(CO)_(n)— in whichn is 0 or 1, C represents (C₁-C₆)alkylene or (C₂-C₆)alkenylene and arylis optionally substituted by one or more radicals T; (C₆-C₁₈)aryl fusedto a saturated or unsaturated heterocycle as defined above, optionallysubstituted by one or more radicals T; (C₂-C₁₀)alkynyl; T is chosen froma halogen atom; (C₆-C₁₈)aryl; (C₁-C₆)alkyl; (C₁-C₆)alkoxy; nitro;carboxyl; (C₁-C₆)alkoxycarboxyl; and T can represent oxo in the casewhere it substitutes a saturated or unsaturated heterocycle; or Trepresents (C₁-C₆)alkoxycarbonyl(C₁-C₆)alkyl; or(C₁-C₆)alkylcarbonyl((C₁-C₆)alkyl)_(n)- in which n is 0 or 1.

The term “halogen atom” means a chlorine, bromine, iodine or fluorineatom. The monocyclic, bicyclic or tricyclic aromatic heterocyclic groupspreferably comprise one or more hetero atoms generally chosen from O, Sand N, optionally in oxidised form (in the case of S and N). Preferably,at least one of the monocycles constituting the heterocycle containsfrom 1 to 4 endocyclic hetero atoms and better still from 1 to 3 heteroatoms.

Preferably, the heterocycle consists of one or more monocycles, each ofwhich is 5- to 8-membered.

Examples of 5- to 8-membered monocyclic heteroaryls are especiallypyridine, furan, thiophene, pyrrole, imidazole, thiazole, isoxazole,isothiazole, furazane, pyridazine, pyrimidine, pyrazine, thiazines,oxazole, pyrazole, oxadiazole, triazole and thiadiazole.

Examples of bicyclic heteroaryls in which each monocycles is 5- to8-membered are chosen from indolizine, indole, isoindole, benzofuran,benzothiophene, indazole, benzimidazole, benzothiazole, benzofurazane,benzothiofurazane, purine, quinoline, isoquinoline, cinnoline,phthalazine, quinazoline, quinoxaline, naphthyridines, pyrazolotriazine(such as pyrazolo-1,3,4-triazine), pyrazolopyrimidine and pteridine.

Preferred heteroaryls that may be mentioned include quinolyl, pyridyl,benzothiazolyl and triazolyl.

The tricyclic heteroaryls in which each monocycle is 5- to 8-memberedare chosen, for example, from acridine, phenazine and carbazole.

The term “alkylenediyl chain” means a divalent radical of linear orbranched aliphatic hydrocarbon-based type derived from the alkyl groupsdefined above by stripping out a hydrogen atom. Preferred examples ofalkylenediyl chains are chains —(CH₂)_(k)— in which k represents aninteger chosen from 2, 3, 4, 5 and 6 and >C(CH₃)₂ and —CH₂—C(CH₃)₂—CH₂—chains. The alkylenedioxy chains denote —O-Alk-O— chains in which Alkrepresents linear or branched alkylene, it being understood thatalkylene is as defined above for alkylenediyl. Preferred meanings of—O-Alk-O— are, for example, —O—C(CH₃)₂—O or —O—CH₂—CH₂—O—.

The term “alkenylene” defines an unsaturated alkylene chain containingone or more ethylenic unsaturations, preferably one to three ethylenicunsaturations. Examples of alkylene chains are —CH═CH— or —CH═CH—CH═CH—.

Examples of C₃-C₁₀ cycloalkyl groups are especially cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl orcyclodecyl groups.

Saturated or unsaturated, monocyclic 5- to 8-membered heterocycles aresaturated, or unsaturated, derivatives of aromatic heterocycles.

Mention may be made more particularly of morpholine, piperidine,thiazolidine, oxazolidine, tetrahydrothienyl, tetrahydrofuryl,pyrrolidine, isoxazolidine, imidazolidine or pyrazolidine.

The term “alkynyl” means an aliphatic hydrocarbon-based group containingone or more unsaturations of acetylenic type. Preferred examples are—C≡C—.

Another preferred group of compounds of the invention consists of thecompounds of the formula I in which R¹ represents a (C₆-C₁₀)aryl group,preferably phenyl, which is optionally substituted and/or fused to acarbocyclic or heterocyclic monocyclic 5- to 8-membered nucleuscontaining from 0 to 4 hetero atoms chosen from O, N and S, which isitself optionally substituted; an optionally substituted C₂-C₁₀ alkenylgroup; a hydrogen atom; R² and R³ independently represent a hydrogenatom; (C₆-C₁₀)aryl, preferably optionally substituted phenyl; or R² andR³ together represent a C₅-C₈ alkylene chain; and

R represents a hydrogen atom; a C₁-C₁₀ alkyl group; a(C₆-C₁₀)aryl(C₁-C₁₀)alkyl group.

Another preferred subgroup of compounds of the invention consists of thecompounds of the formula I in which, when R¹ represents a substituted(C₆-C₁₀)aryl, the aryl nucleus is substituted by one or more of thefollowing radicals: trifluoromethyl; a halogen atom; a monocyclic,bicyclic or tricyclic aromatic heterocyclic group comprising one or morehetero atoms chosen from O, N and S; and optionally substituted by oneor more radicals T as defined below; a group Het-CO— in which Hetrepresents an aromatic heterocyclic group as defined above, optionallysubstituted by one or more radicals T; a C₁-C₆ alkylenediyl chain; aC₁-C₆ alkylenedioxy chain; nitro; cyano; (C₁-C₁₀)alkyl;(C₁-C₁₀)alkylcarbonyl; (C₁-C₁₀)alkoxycarbonyl-A- in which A represents(C_(r) C₆)alkylene, (C₂-C₆)alkenylene or a bond; (C₃-C₁₀)cycloalkyl;trifluoromethoxy; di(C₁-C₁₀)alkylamino; (C₁-C₁₀)alkoxy(C₁-C₁₀)alkyl;(C₁-C₁₀)alkoxy; (C₆-C₁₈)aryl optionally substituted by one or moreradicals T; (C₆-C₁₈)aryl(C₁-C₁₀)alkoxy-(CO)_(n)— in which n is 0 or 1and aryl is optionally substituted by one or more radicals T;(C₆-C₁₈)aryloxy(CO)_(n)— in which n is 0 or 1 and in which aryl isoptionally substituted by one or more radicals T; (C₆-C₁₈)arylthio inwhich aryl is optionally substituted by one or more radicals T;(C₆-C₁₈)aryloxy(C₁-C₁₀)alkyl(CO)_(n)— in which n is 0 or 1 and in whicharyl is optionally substituted by one or more radicals T; a saturated orunsaturated, monocyclic 5- to 8-membered heterocycle comprising one ormore hetero atoms chosen from O, N and S, optionally substituted by oneor more radicals T; (C₆-C₁₈)arylcarbonyl optionally substituted by oneor more radicals T; (C₆-C₁₈)arylcarbonyl-B—(CO)_(n)— in which n is 0 or1; B represents (C₁-C₆)alkylene or (C₂-C₆)alkenylene and aryl isoptionally substituted by one or more radicals T;(C₆-C₁₈)aryl-C—(CO)_(n)— in which n is 0 or 1, C represents(C₁-C₆)alkylene or (C₂-C₆)alkenylene and aryl is optionally substitutedby one or more radicals T; (C₆-C₁₈)aryl fused to a saturated orunsaturated heterocycle as defined above, optionally substituted by oneor more radicals T; (C₂-C₁₀)alkynyl; T is chosen from a halogen atom;(C₆-C₁₈)aryl; (C₁-C₆)alkyl; (C₁-C₆)alkoxy; nitro; carboxyl;(C₁-C₆)alkoxycarboxyl; and T can represent oxo in the case where itsubstitutes a saturated or unsaturated heterocycle; or alternatively Trepresents (C₁-C₆)alkoxycarbonyl(C₁-C₆)alkyl; or(C₁-C₆)alkylcarbonyl((C₁-C₆)alkyl)_(n)- in which n is 0 or 1.

Another group of preferred compounds consists of the compounds of theformula I for which, when R¹ represents aryl, R¹ is phenyl.

Another group of preferred compounds consists of the compounds for whichR¹ represents (C₁-C₁₀)alkyl, preferably (C₁-C₃)alkyl, and R² and R³represent, independently of each other, H or optionally substituted(C₆-C₁₈) aryl.

Another group of preferred compounds consists of the compounds for whichR² is H and R³ represents unsubstituted aryl, preferably unsubstitutedphenyl.

Another group of preferred compounds consists of the compounds forwhich, when R represents (C₁-C₁₀)alkylaryl, preferably benzyl, R¹ and R³represent unsubstituted aryl, preferably phenyl.

A first even more preferred group of compounds of the invention consistsof the compounds of the formula I in which R¹ represents anunsubstituted aryl group, R² represents H, R³ represents unsubstitutedaryl and R is H.

A second even more preferred group of compounds of the inventionconsists of the compounds of the formula I in which R¹ representsunsubstituted aryl, R²═H, R³ is unsubstituted aryl and R=alkyl.

A third even more preferred group of compounds of the invention consistsof the compounds of the formula I in which R¹=unsubstituted aryl, R²═H,R³=unsubstituted aryl and R=alkylaryl.

A fourth even more preferred group of compounds of the inventionconsists of the compounds of the formula I in which R¹=substituted aryl,R²═H, R³=unsubstituted aryl and R═H.

A fifth even more preferred group of compounds of the invention consistsof the compounds of the formula I in which R¹=represents substitutedaryl, R²═H, R3 is unsubstituted aryl and R=alkyl.

A sixth even more preferred group of compounds of the invention consistsof the compounds of the formula I in which R¹ represents substitutedaryl, R²═H, R³ is unsubstituted aryl and R=alkylaryl.

A seventh even more preferred group of compounds of the inventionconsists of the compounds of the formula I in which R¹ represents alkyl,R²═H, R³ is unsubstituted aryl and R═H.

An eighth even more preferred group of compounds of the inventionconsists of the compounds of the formula I in which R¹ represents alkyl,R²═H, R³ is unsubstituted aryl and R=alkyl.

A ninth even more preferred group of compounds of the invention consistsof the compounds of the formula I in which R¹ represents alkyl, R²═H, R³is unsubstituted aryl and R=alkylaryl.

The compounds that are more particularly preferred are chosen from:

-   methyl(R,S)-2-methoxy-4-phenylbut-3-enoate-   (R,S)-2-methoxy-4-phenylbut-3-enoic acid-   methyl(R,S)-2-propoxy-4-phenylbut-3-enoate-   (R,S)-2-propoxy-4-phenylbut-3-enoic acid-   benzyl(R,S)-2-phenoxy-4-phenylbut-3-enoate-   methyl(R,S)-2-trifluoromethylphenoxy-4-phenylbut-3-enoate-   (R,S)-2-phenoxy-4-phenylbut-3-enoic acid-   (R,S)-2-trifluoromethylphenoxy-4-phenylbut-3-enoic acid (Z and E    forms).

The compounds of the invention can be prepared by reaction of a compoundof the formula II

in which R², R³ and R are as defined above for formula I and Xrepresents —OH or a halogen atom, such as chlorine,with an alcohol of the formula R¹—OH.

This reaction is preferably performed in a polar aprotic solvent, suchas a linear or cyclic ether, for example diethyl ether, di-tert-butylether, diisopropyl ether or dimethoxyethane, or alternatively, such asdioxane or tetrahydrofuran, tetrahydrofuran and dimethoxyethane beingpreferred.

According to one preferred embodiment of the invention, the molar ratioof the compound of the formula II to the alcohol R¹—OH ranges between 1and 1.5, an approximately stoichiometric ratio of between 1 and 1.3 andpreferably between 1 and 1.1 being desirable.

In order to facilitate the reaction, it is desirable to add to themedium a coupling agent, such as a lower alkyl (i.e. C₁-C₆ alkyl)diazodicarboxylate, for example ethyl diazodicarboxylate.

When it is present in the reaction medium, the coupling agent isincorporated into the medium in a proportion of from 1 to 5 equivalentsand better still in a proportion of from 1 to 3 equivalents, for examplein a proportion of from 1 to 2 molar equivalents relative to the initialamount of compound of the formula II.

Preferably, it is also recommended to introduce a phosphine into thereaction medium, such as triphenylphosphine. In this case, the molarratio of triphenylphosphine to the compound of the formula II ispreferably maintained between 1 and 5, for example between 1 and 3 andespecially between 1 and 2.

When X represents —OH, the reaction temperature generally ranges between−15° C. and 50° C., it being understood that temperatures of between−15° C. and 10° C. are desirable in the presence of a coupling agent.

When X represents a halogen atom, the compound of the formula II isrepresented by formula II_(Hal) below:

in which R, R² and R³ are as defined above and Hal represents a halogenatom.

With a compound of the formula II_(Hal), as defined above, a base isintroduced into the reaction medium, preferably a mineral base chosenfrom sodium hydroxide, potassium hydroxide, sodium hydrogen carbonate,potassium hydrogen carbonate, sodium carbonate and potassium carbonate.Usually, the molar ratio of the base to the compound of the formula IIranges between 1 and 5 and better still between 1 and 3.

When X represents a halogen atom, the reaction temperature generallyranges between 10° C. and 120° C., for example between 60° C. and 100°C. and better still between 70° C. and 90° C.

When X represents halogen, for example chlorine, the compounds of theformula I of the invention can be obtained according to the followingreaction scheme, in which R, R¹, R² and R³ are as defined above:

The compounds of the formula I can be prepared by selective reduction ofthe oxo function alpha to the function —COOR in the compound of theformula III below:

in which R, R² and R³ are as defined above,

via the action of a suitable hydride, followed by alkylation of thehydroxyl function formed.

Examples of suitable hydrides are especially sodium borohydride, lithiumborohydride, tributylammonium borohydride, lithium triethylborohydrideand sodium cyanoborohydride, sodium borohydride being preferred.

The reaction is preferably performed in a solvent, such as a loweralkanol, such as methanol or propanol, at a temperature of between −15°C. and 20° C. and preferably between −10° C. and +10° C.

For this reaction, the molar ratio of the hydride to the compound of theformula III ranges between 0.1 and 10 equivalents. When the hydride isNaBH₄, 0.2 to 0.5 equivalent of NaBH₄ is sufficient.

The alkylation of the intermediate compound, obtained via the action ofthe hydride

in which R², R³ and R are as defined above for formula I, can beperformed in a manner that is conventional per se.

One way of performing the process consists simply in reacting theintermediate compound of the formula IV with the appropriate alkylhalide of the formula R¹—Y in which Y is a halogen atom, preferablyiodine, in the presence of silver oxide, Ag₂O.

For this reaction, a large excess of the alkylating agent of the formulaR¹—Y, for example from 5 to 200 equivalents and better still between 100and 150 equivalents relative to the initial amount of compound of theformula IV, will advantageously be used.

As regards the amount of Ag₂O, it is desirable for it to range between 2and 12 equivalents, for example between 4 and 10 equivalents.

The compounds of the formula I can also be prepared via the action of analcohol of the formula R¹—OH on a compound of the formula V

in which R², R³ and R are as defined above, in the presence of a rhodiumII complex, such as rhodium II tetraacetate of the formula Rh₂(OAc)₄.

This reaction is preferably performed in a polar aprotic solvent, suchas an optionally chlorinated aromatic hydrocarbon, for example benzene,toluene, xylene or a chlorobenzene, benzene being preferred.

A molar ratio of the alcohol R¹—OH to the compound of the formula Vranging between 1 and 10, for example between 1 and 5 and better stillbetween 2 and 4, is preferably used for this reaction.

It is desirable for the rhodium complex to be present in a proportion offrom 10⁻³ to 10⁻¹ equivalent relative to the compound of the formula V,a ratio of the rhodium complex to the compound of the formula V ofbetween 0.01 and 0.10 and better still between 0.01 and 0.05 beingpreferred.

The reaction temperature is usually between 50° C. and 120° C., forexample between 60° C. and 100° C.

The compounds of the formula I in which R represents H can be obtainedby saponification of the corresponding compounds of the formula I inwhich R represents C₁-C₁₀ alkyl. The saponification can be performed viathe action of a base, such as a mineral base chosen from LiOH, KOH,NaOH, NaHCO₃, KHCO₃, Na₂CO₃ and K₂CO₃. The molar amount of base to beused generally ranges from 1 to 20 equivalents and preferably from 1 to12 equivalents depending on the strength of the selected base.

More particularly, in the case of LiOH, it is preferred to employ from 8to 12 equivalents of base relative to the amount of ester of the formulaI present in the reaction medium.

The reaction is preferably performed in a solvent of polar protic typeand more preferably in a mixture of lower (C₁-C₄) alkanol and water,such as a mixture of ethanol and water or methanol and water.

The reaction temperature advantageously ranges between 35° C. and 120°C. and better still between 40° C. and 100° C.

The compounds of the formula I in which R¹ represents aryl substitutedby a monocyclic, bicyclic or tricyclic aromatic heterocyclic groupcomprising one or more hetero atoms chosen from O, N and S, andoptionally substituted by one or more radicals T as defined above; oralternatively R¹ represents an aryl group optionally substituted by oneor more radicals T, can be prepared by reaction of the correspondingcompound of the formula I in which R¹ represents aryl substituted by ahalogen atom, such as chlorine, bromine or iodine, via the action of acompound of the formula VI:

in which G represents a monocyclic, bicyclic or tricyclic aromaticheterocyclic group comprising one or more hetero atoms chosen from O, Nand S, and optionally substituted by one or more radicals T as definedabove when R¹, in the final compound, represents aryl substituted bysuch a heterocyclic group, or alternatively G represents aryl optionallysubstituted by one or more radicals T when, in the final compound, R¹represents aryl substituted by an aryl group, which is itself optionallysubstituted by one or more radicals T.

Advantageously, from 1.5 to 5 equivalents and preferably from 1.5 to 3equivalents of the compound of the formula VI are employed relative tothe amount of compound of the formula I present in the reaction medium.

This reaction is preferably performed in a polar aprotic solvent in thepresence of a palladium(0) complex and a base.

A linear or cyclic ether, such as those defined above is moreparticularly suitable as solvent. Dimethoxyethane is preferred.

The base that will be used is any of the mineral bases mentioned aboveand advantageously Na₂CO₃. For example, from 1.5 to 5 equivalents andpreferably from 1.5 to 3 equivalents of base, relative to the amount ofcompound of the formula I, can be introduced into the reaction medium.

According to one preferred embodiment, the amounts of base and ofcompound of the formula VI are equivalent. The amount of palladium(0)complex used is catalytic. Usually, from 0.001 to 1 equivalent andpreferably from 0.01 to 0.1 equivalent of the said complex is used. Anexample of a palladium(0) complex that can be used istetraphenylpalladium(0).

The reaction temperature advantageously ranges between 50° C. and 120°C. and preferably between 70° C. and 90° C.

The invention also relates to pharmaceutical compositions comprising apharmaceutically effective amount of a compound of the formula (I) asdefined above in combination with one or more pharmaceuticallyacceptable vehicles.

In the present description, the expression “pharmaceutically effectiveamount” should be understood as defining the amount of an activematerial or of a pharmaceutical agent that will make it possible toinduce the biological or medical response of an animal or human tissueor system, this biological or medical response corresponding to theresponse desired, for example, by a researcher or a clinician.

In addition, the expression “therapeutically effective amount”corresponds to any amount which, in comparison with a correspondingindividual who has not received such amount, results in an improvedtreatment, curing, better prevention, or improvement of a pathologicalcondition, a disorder or one or more side effects, or alternativelyresults in a reduction in the degree of advancement of a disease orpathological disorder. The expression described above also includes inits meaning amounts that are effective for improving a normalphysiological function.

Thus, the pharmaceutical compositions according to the present inventioncan be administered orally in the form of tablets, gel capsules orgranules with immediate release or controlled release, intravenously inthe form of an injectable solution, transdermally in the form of anadhesive transdermal device, or locally in the form of a solution, creamor gel.

A solid composition for oral administration is prepared by adding to theactive principle a filler and, where appropriate, a binder, adisintegrating agent, a lubricant, a colorant or a flavour enhancer, andby forming the mixture into a tablet, a coated tablet, a granule, apowder or a capsule.

Examples of fillers include lactose, corn starch, sucrose, glucose,sorbitol, crystalline cellulose and silicon dioxide, and examples ofbinders include poly(vinyl alcohol), poly(vinyl ether), ethylcellulose,methylcellulose, acacia, gum tragacanth, gelatine, shellac,hydroxypropylcellulose, hydroxy-propylmethylcellulose, calcium citrate,dextrin and pectin. Examples of lubricants include magnesium stearate,talc, polyethylene glycol, silica and hardened plant oils. The colorantmay be any of those permitted for used in medicaments. Examples offlavour enhancers include cocoa powder, mint in herb form, aromaticpowder, mint in oil form, borneol and cinnamon powder. Obviously, thetablet or granule may be suitably coated with sugar, gelatine or thelike.

An injectable form comprising the compound of the present invention asactive principle is prepared, where appropriate, by mixing the saidcompound with a pH regulator, a buffer agent, a suspension agent, asolubiliser, a stabiliser, an isotonic agent and/or a preserving agent,and by converting the mixture into a form for intravenous, subcutaneousor intramuscular injection, according to a standard process. Whereappropriate, the injectable form obtained can be freeze-dried via astandard process.

Examples of suspension agents include methylcellulose, polysorbate 80,hydroxyethylcellulose, acacia, powdered gum tragacanth, sodiumcarboxymethylcellulose and polyethoxylated sorbitan monolaurate.

Examples of solubilisers include castor oil solidified withpolyoxyethylene, polysorbate 80, nicotinamide, polyethoxylated sorbitanmonolaurate and the ethyl ester of castor oil fatty acid.

In addition, the stabiliser encompasses sodium sulfite, sodiummetasulfite and ether, while the preserving agent encompasses methylp-hydroxybenzoate, ethyl p-hydroxybenzoate, sorbic acid, phenyl, cresoland chlorocresol.

A subject of the present invention is also the use of a compound of theformula I of the invention for the preparation of a medicament for theprevention or treatment of dyslipidaemia, atherosclerosis and diabetes.

The examples that follow illustrate the invention in a non-limitingmanner.

In the proton nuclear magnetic resonance data (300 MHz NMR), thefollowing abbreviations have been used: s for singlet, d for doublet, tfor triplet, q for quartet, o for octet and m for complex multiplet. Thechemical shifts δ are expressed in ppm; m.p. represents the meltingpoint.

EXAMPLES Example 1 Process for the preparation ofmethyl(R,S)-2-hydroxy-4-phenylbut-3-enoate 1.1—Preparation of methyl2-oxo-4-phenylbut-3-enoate

2 ml of concentrated sulfuric acid are added dropwise to a suspension of5.9 g (30 mmol) sodium 2-oxo-4-phenylbut-3-enoate (1) (Synth. Commun.,(1996), 26(11), 2231) in 100 ml of methanol. The mixture is refluxed for8 hours and stirred overnight at room temperature. A light insolublematerial is filtered off and the filtrate is concentrated to half itsvolume and poured into 300 ml of water. The pasty solid obtained isextracted with dichloromethane and washed with aqueous 5% sodiumhydrogen carbonate solution and then with water. The resulting solutionis dried over sodium sulfate. The solvent is evaporated off undervacuum. The residue (4.2 g) is purified by flash chromatography (SiO₂,70/30 CH₂Cl₂/heptane).

1.7 g (30% yield) of a bright yellow solid melting at 70-71° C. areobtained.

¹H NMR (CDCl₃, 300 MHz): 3.86 (3H, s); 7.31 (1H, d, J=16 Hz); 7.27-7.58(5H, m); 7.80 (1H, d, J=16 Hz).

1.2—Process for the preparation ofmethyl(R,S)-2-hydroxy-4-phenylbut-3-enoate

0.27 g (7 mmol) of sodium borohydride is added portionwise, over about10 minutes, to a solution of 4.2 g (22 mmol) of methyl2-oxo-4-phenylbut-3-enoate in 150 ml of methanol, cooled to 0° C. Themixture is stirred for 10 minutes between 0° C. and +5° C. and thenallowed to warm to room temperature. The resulting mixture is evaporatedunder vacuum at 40° C., the residue is taken up in 100 ml of water, theresulting mixture is extracted with dichloromethane and the organicextracts are dried over sodium sulfate. The solvent is evaporated offunder vacuum. The residue (3.7 g) is purified by flash chromatography(SiO₂, 80/20 heptane/ethyl acetate).

2.2 g (52% yield) of a yellow oil are obtained.

¹H NMR (CDCl₃, 300 MHz): 3.00 (1H, OH); 3.70 (3H, s); 4.73-4.75 (1H, d,J=6 Hz); 6.11-6.17 (1H, dd, J=16 Hz, J=6 Hz); 6.67-6.73 (1H, d, J=16Hz); 7.15-7.30 (5H, m).

Example 2 Process for the preparation ofmethyl(R,S)-2-methoxy-4-phenylbut-3-enoate

1.8 g (8 mmol) of freshly prepared silver oxide are added to a solutionof 225 mg (1.2 mmol) of the compound obtained in Example 1 in 10 ml ofmethyl iodide. The mixture is stirred for 24 hours at room temperatureand then diluted with 10 ml of dichloromethane. The insoluble materialis filtered off and the filtrate is then evaporated under vacuum. 210 mg(85% yield) of a colourless oil are obtained.

Example 3 Process for the preparation of(R,S)-2-methoxy-4-phenylbut-3-enoic acid

42 ml (42 mmol) of aqueous 1M lithium hydroxide monohydrate solution areadded to a solution of 0.87 g (4.2 mmol) of the compound obtained inExample 2 in 80 ml of methanol. The mixture is refluxed for 4 hours.After leaving to stand overnight, the mixture is evaporated under vacuumand the residue is taken up in 40 ml of water. This mixture is washedwith 2×30 ml of ethyl ether and the aqueous phase is acidified withdilute hydrochloric acid. The resulting aqueous phase is extracted withethyl ether, the organic extracts are dried over sodium sulfate and thesolvent is evaporated off under vacuum. The residue (0.65 g) is purifiedby flash chromatography (SiO₂, 95/5 dichloromethane/methanol). 50 mg (6%yield) of a yellow oil are obtained.

Example 4 Process for the preparation of(R,S)-2-n-propoxy-4-phenylbut-3-enoic acid

480 mg (2 mmol) of the compound obtained in Example 3, 10 ml of ethanol,1 ml of water and 270 mg (4 mmol) of potassium hydroxide pellets arerefluxed for 4 hours. The mixture is evaporated under vacuum and theresidue is taken up in 25 ml of water. This mixture is washed with ethylether and the aqueous phase is acidified with dilute hydrochloric acid.The resulting mixture is extracted with ethyl ether, the organicextracts are dried over sodium sulfate and the solvent is evaporated offunder vacuum. The residue (310 mg) is purified by flash chromatography(SiO₂, 80/20 heptane/ethyl acetate). 45 mg (10% yield) of a yellowishoil are obtained.

Illustration of the reaction scheme of Examples 1 to 4, R¹=alkyl.

Example 5 Process for the preparation ofmethyl(R,S)-4-phenyl-2-(4-trifluoromethylphenoxy)but-3-enoate

300 mg (0.67 mmol) of dimeric rhodium acetate are added to a solution of14.6 g of 4-trifluoromethylphenol in 150 ml of benzene. The mixture isbrought to reflux and a solution of 6.2 g (30 mmol) of methyl4-phenyl-2-diazobut-3-enoate (6) (Tetrahedron Lett., (1988), 29(9),975-978) in 60 ml of benzene is added dropwise over one hour. Themixture is allowed to cool to room temperature and the solvent is thenevaporated off under vacuum. The residue is purified twice by flashchromatography. 460 mg (4.6% yield) of a yellow oil which crystallisesare obtained.

Example 6 Process for the preparation of(R,S)-4-phenyl-2-(4-trifluoro-methylphenoxy)but-3-enoic acid

12.2 ml (12.2 mmol) of aqueous 1M lithium hydroxide monohydrate solutionare added to a solution of 410 mg (1.22 mmol) of the compound obtainedin Example 5 in 20 ml of sodium hydroxide. The mixture is stirred forone hour at room temperature and the solvent is then evaporated offunder vacuum. The residue is taken up in 20 ml of water and the solutionobtained is washed with ethyl ether. The aqueous phase is acidified withdilute hydrochloric acid and extracted with ethyl ether. The organicextracts are dried over sodium sulfate and the solvent is evaporated offunder vacuum. The residue is purified by preparative LC/MS. Two pureproducts (8) and (9) corresponding to the two Z and E forms (5.5 mg and7.8 mg, respectively) are recovered.

Illustration of the reaction scheme of Examples 5 and 6, R¹=substitutedaryl (trifluoromethylphenyl), steps a) and b)

Results

The activity of the compounds of the invention leading to ahypolipidaemiant and hypoglycaemiant effect was demonstrated in vitro byperforming the following tests:

The measurement of the PPAR activation was performed according to atechnique described by Lehmann et al. (J. Biol. Chem., 270, (1995),12953-12956).

CV-1 cells (monkey kidney cells) are co-transfected with an expressionvector for the chimeric proteins PPARα-Gal4 or PPARγ-Gal4 and with a“reporter” plasmid that allows the expression of the luciferase geneplaced under the control of a promoter containing Gal4 responseelements.

The cells are plated into 96-well microplates and co-transfected using acommercial reagent with the reporter plasmid (pG5-tk-pGL3) and theexpression vector for the chimeric protein (PPARα-Gal4 or PPARα-Gal4).After incubating for 4 hours, whole culture medium (comprising 10%foetal calf serum) is added to the wells. After 24 hours, the medium isremoved and replaced with whole medium comprising the test products (50μM final). The products are left in contact with the cells for 18 hours.The cells are then lysed and the luciferase activity is measured using aluminometer. A PPAR activation factor can then be calculated by means ofactivation of the expression of the reporter gene induced by the product(relative to the control cells that have not received any product).

By way of example, the compound

at a concentration of 50 μM, activates the chimeric protein PPARα-Gal-4by a factor of 2.3, and the chimeric protein PPARα-Gal4 by a factor of6.4. In the absence of the binding domain for the PPAR α or γ ligand(vector expressing Gal4 alone), the luciferase activity measured in thepresence of this product is zero.

1. A method of treating dyslipidaemia, atheroschlerosis or diabetescomprising administering to a patient in need thereof a therapeuticallyeffective amount of a compound of the formula I:

in which R¹ represents a (C₆-C₁₈)aryl group, which is optionallysubstituted and/or optionally fused to a saturated or unsaturated,monocyclic or polycyclic 5- to 8-membered nucleus optionally containingone or more hetero atoms chosen from O, N and S, said nucleus itselfbeing optionally substituted; an optionally substituted, saturated,unsaturated or aromatic 5- to 8-membered monocyclic heterocyclic groupcontaining one or more hetero atoms chosen from O, N and S; anoptionally substituted C₂-C₁₀ alkenyl group; or a C₁-C₁₀ alkyl group R²and R³ independently represent a hydrogen atom an optionally substituted(C₆-C₁₈)aryl; or alternatively R² and R³ together represent a C₃-C₆alkylene chain; and R represents a hydrogen atom; a C₁-C₁₀ alkyl groupor a (C₆-C₁₈)aryl(C₁-C₁₀)alkyl group; or a salt thereof with acids orbases, or a pharmaceutically acceptable derivative, or stereoisomerthereof, including mixtures thereof in all proportions with the provisothat the following compounds are excluded from the protection: thecompounds where R³=phenyl, R=ethyl, R¹=ethyl or phenyl and R²═H.
 2. Amethod according to claim 1 of the formula I in which R¹ represents a(C₆-C_(to))aryl group, which is optionally substituted and/or fused to acarbocyclic or heterocyclic monocyclic 5- to 8-membered nucleuscontaining from 0 to 4 hetero atoms chosen from O, N and S, which isitself optionally substituted; an optionally substituted C₂-C₁₀ alkenylgroup; a hydrogen atom; R² and R³ independently represent a hydrogenatom or (C₆-C_(to))aryl, or R² and R³ together represent a C₃-C₆alkylene chain; and R represents a hydrogen atom; a C₁-C₁₀ alkyl group;a (C₆-C₁₀)aryl(C₁-C₁₀)alkyl group and also the pharmaceuticallyacceptable salts, and stereoisomers thereof, including mixtures thereofin all proportions.
 3. A method according to claim 1, wherein when R¹represents substituted (C₆-C₁₀)aryl, the aryl nucleus is substituted byone or more of the following radicals: trifluoromethyl; a halogen atom;a monocyclic, bicyclic or tricyclic aromatic heterocyclic groupcomprising one or more hetero atoms chosen from O, N and S, andoptionally substituted by one or more radicals T as defined below; agroup Het-CO— in which Het represents an aromatic heterocyclic group asdefined above, optionally substituted by one or more radicals T; a C₁-C₆alkylenediyl chain; a C₁-C₆ alkylenedioxy chain; nitro; cyano;(C₁-C₁₀)alkyl; (C₁-C₁₀)alkylcarbonyl; (C₁-C₁₀)alkoxycarbonyl-A- in whichA represents (C₁-C₆)alkylene, (C₂-C₆)alkenylene or a bond;(C₃-C₁₀)cycloalkyl; trifluoromethoxy; di(C₁-C₁₀)alkylamino;(C₁-C₁₀)alkoxy(C₁-C₁₀)alkyl; (C₁-C₁₀)alkoxy; (C₆-C₁₈)aryl optionallysubstituted by one or more radicals T;(C₆-C₁₈)aryl(C₁-C₁₀)alkoxy-(CO)_(n)— in which n is 0 or 1 and aryl isoptionally substituted by one or more radicals T;(C₆-C₁₈)aryloxy(CO)_(n)— in which n is 0 or 1 and in which aryl isoptionally substituted by one or more radicals T; (C₆-C₁₈)arylthio inwhich aryl is optionally substituted by one or more radicals T;(C₆-C₁₈)aryloxy(C₁-C₁₀) alkyl(CO)_(n)— in which n is 0 or 1 and in whicharyl is optionally substituted by one or more radicals T; a saturated orunsaturated, monocyclic 5- to 8-membered heterocycle comprising one ormore hetero atoms chosen from O, N and S, optionally substituted by oneor more radicals T; (C₆-C₁₈)arylcarbonyl optionally substituted by oneor more radicals T; (C₆-C₁₈)arylcarbonyl-B—(CO)_(n)— in which n is 0 or1; B represents (C₁-C₆)alkylene or (C₂-C₆)alkenylene and aryl isoptionally substituted by one or more radicals T;(C₆-C₁₈)aryl-C—(CO)_(n)— in which n is 0 or 1, C represents(C₁-C₆)alkylene or (C₂-C₆)alkenylene and aryl is optionally substitutedby one or more radicals T; (C₆-C₁₈)aryl fused to a saturated orunsaturated heterocycle as defined above, optionally substituted by oneor more radicals T; (C₂-C₁₀)alkynyl; T is chosen from a halogen atom;(C₆-C₁₈)aryl; (C₁-C₆)alkyl; (C₁-C₆)alkoxy; nitro; carboxyl;(C₁-C₆)alkoxycarboxyl; and T can represent oxo in the case where itreplaces a saturated or unsaturated heterocycle; or alternatively Trepresents (C₁-C₆)alkoxycarbonyl(C₁-C₆)alkyl; or(C₁-C₆)alkylcarbonyl((C₁-C₆)alkyl)_(n)- in which n is 0 or
 1. 4. Amethod according to claim 1, wherein when R¹ is aryl, R¹ representsphenyl.
 5. A method according to claim 1, wherein R¹ represents (C₁-C₁₀)alkyl, and R² and R³ represent, independently of each other, H oroptionally substituted (C₆-C₁₈) aryl.
 6. A method according to claim 1,wherein R² is H and R³ represents unsubstituted aryl.
 7. A methodaccording to claim 1, wherein when R represents (C₁-C₁₀)alkylaryl, R¹and R³ represent unsubstituted aryl.
 8. A method according to claim 1 ofthe formula I, which is: methyl(R,S)-2-methoxy-4-phenylbut-3-enoate(R,S)-2-methoxy-4-phenylbut-3-enoic acidmethyl(R,S)-2-propoxy-4-phenylbut-3-enoate(R,S)-2-propoxy-4-phenylbut-3-enoic acidbenzyl(R,S)-2-phenoxy-4-phenylbut-3-enoatemethyl(R,S)-2-trifluoromethylphenoxy-4-phenylbut-3-enoate(R,S)-2-phenoxy-4-phenylbut-3-enoic acid(R,S)-2-trifluoromethylphenoxy-4-phenylbut-3-enoic acid (Z and E forms),or a pharmaceutically acceptable derivative, salt or stereoisomerthereof, including mixtures thereof in all proportions.
 9. A process forthe preparation of a compound of the formula I according to claim 1,wherein a halide of the formula R¹—Y in which Y represents a halogenatom and R¹ is (C₁-C₁₀)alkyl, is reacted with a compound having thefollowing formula:

in which R², R³ and R are as defined in claim 1 for formula I, in thepresence of silver oxide.
 10. A process for the preparation of acompound of the formula I according to claim 1, in which R¹ represents(C₆-C₁₀) aryl, which is optionally substituted and/or optionally fusedto a monocyclic heterocyclic saturated or unsaturated 5- to 8-memberednucleus containing one or more hetero atoms chosen from O, N and S,which is itself optionally substituted, characterised in that a compoundof the formula:

in which R², R³ and R are as defined in claim 1 for formula I, isreacted with a compound of the formula:R¹—OH in which R¹ is as defined above, in the presence of rhodiumtetraacetate.
 11. A process for the preparation of a compound of theformula I, characterised in that a compound of the formula as defined inclaim 9 is reacted with a compound of the formula R¹—OH in the presenceof triphenylphosphine and ethyl diazodicarboxylate.
 12. A process forthe preparation of a compound of the formula I according to claim 1,characterised in that a compound of the formula II_(Hal):

in which R², R³ and R are as defined in claim 1 for formula I and Halrepresents a halogen atom, is reacted with a compound of the formulaR¹—OH.
 13. A process for the preparation of a compound of the formula Iaccording to claim 3, Hal being a halogen atom, according to thefollowing reaction scheme, the first step being performed in a polaraprotic solvent in the presence of a palladium(0) complex and a base;the second step being a saponification:

in which reaction scheme G represents a monocyclic, bicyclic ortricyclic aromatic heterocyclic group comprising one or more heteroatoms chosen from O, N and S, and optionally substituted by one or moreradicals T as defined above when R¹, in the final compound, representsaryl substituted by such a heterocyclic group; or alternatively Grepresents aryl optionally substituted by one or more radicals T asdefined in claim 3 when, in the final compound, R¹ represents arylsubstituted by an aryl group, which is itself optionally substituted byone or more radicals T; Hal represents a halogen atom. 14-15. (canceled)16. A method according to claim 2, wherein R¹ is (C₁-C₃)alkyl or aphenyl which is optionally substituted and/or fused to a carbocyclic orheterocyclic monocyclic 5- to 8-membered nucleus containing from 0 to 4hetero atoms chosen from O, N and S, which is itself optionallysubstituted.
 17. A method according to claim 2, wherein R² and R³independently represent a substituted or unsubstituted phenyl.
 18. Amethod according to claim 7, wherein R represents benzyl.